However, unlike its famous counterparts such as Chichen Itza, access is strictly controlled due to it sitting on private property, one of the largest ex-haciendas in Guanajuato.

These people used astronomical criteria, religious beliefs and agricultural cycles to select the Laja River Valley for the construction of this Pre-Hispanic burial site.

The site was dedicated to the Moon, the Sun and Venus, as demonstrated by archaeoastronomical studies conducted by the National Institute of Anthropology and History (INAH).

The close relationship between the architectural complex construction and star cycles is mainly observed in complex A or the House of the Thirteen Heavens, a vital space for the celestial observation, whose sunken patio functioned as water mirror from which the priests could look at the sky and interpret aspects in the interests for the agricultural cycle.

The buildings on site are located on a plateau that was artificially filled to obtain an 18° tilt, thus ancient Otomi managed the Sun to pass over various points of the architectural complex, marking calendar dates linked to survival control as well as seeding and harvesting activities.

The Seven onsite architectural structures, considered monumental as exceed the human scale, are huge step pyramids with sloped sides of different sizes and styles that form various spaces, such as sunken patios, squares, esplanades, a 1,000-metre-long (3,300 ft) road.

This tradition is characterized by its advanced ceramic industry and its complex religious expressions, which indicate at an early consolidation of a group in power.

[3] Also identified as the regional development stage, the Sunken Patio tradition covers the classic and epiclassical periods (350 to 900 AD.)

Still heavily argued and linked to the agricultural frontier withdrawal, new hypotheses about Toltec presence propose that it coincided with the arrival of proto-Toltec groups to the Basin of Mexico, between 900 and 1000 AD., and not with the collapse of Tula, Hidalgo, around 1200 AD.

Special note for Complex A or the House of the Thirteen Heavens - critical space for celestial observation - consists of a sunken patio, a pyramidal basement (over 15 m high) and platforms that close to the East, North and South as a whole.

Funeral findings in this complex have given rise to forensic studies that have provided information about cultural and cranial deformation, burial, ancestral worship and rituals associated with the foundation of workplace practices.

Basement A, with the largest volume and complexity, is composed of different elements: step pyramid, stairways, building or upper temple, central and side patios, esplanade and an avenue.

As in most cases, the largest volume basement was found at the center, the remainder is distributed in all directions, configuring various squares and esplanades.

The patio geometry in relation to the plaza-esplanade and eastern road denotes the domain reached by the Toltec-Chichimec architects in design and construction.

It was built with stone walls plastered with mud and stucco (mixture of lime and sand) and painted red oxide (towards its penultimate occupation) and ochre (last).

It is worth noting that in this structure patio remains of a stone anthropomorphic sculpture were found, consistent with what would be the head and left foot of some postclassical individual from the northern center of Mesoamerica.